Motion converting means



March 24, 1953 G, PINAZZA MOTION CONVERTING MEANS 3 Sheets-Sheet l Filed May l2, 1949 BY /fu/h/ Aar March 24, 1953 G. PlNAzzA 2,632,331

MOTION CONVERTING MEANS Filed May 12, 1949 5 Sheets-Sheet 2 March 24, 1953 G. plNAzZA MOTION CONVERTING MEANS 5 Sheets-Sheet 3 Filed May l2, 1949 Patented Mar. 24, 1953 UNITED STATES PATENT OFFICE 2,632,331 MOTION CONVERTING MEANS Giosu Pinazza, Milan, Italy Application May 12, 1949, Serial No. 92,842

(Cl. 'i4-61) Claims. 1

This invention relates to a percussion apparatus actuated by the centrifugal force developed by revolving eccentric masses.

Percussion tools actuated by revolving eccentric masses are already known. The rotary motion of such masses is not uniform, but periodically accelerated and retarded in the course of each Whole revolution, so that the resulting centrifugal force will be great in the direction of useful percussion, and small in the opposite direction, i. e. on the return stroke. Such a result is preferably obtained by means of at least one pair of crank arms, one of which is secured to the driving shaft and is revolving at essentially uniform speed, while the other is secured to the ec-v centric masses, the lengths of such arms being of a periodically variable ratio during each revolution of the masses.

The object of the invention is to provide a percussion apparatus of the aforedescribed type. Other objects of my invention are to provide a percussion apparatus which is of simple construction and will insure a reliable and eflicient operation.

My percussion apparatus is substantially characterized by the fact that the reciprocating percussion element on which the support or supports .for the revolving eccentric masses are provided vshows at least one axial hole on the side opposite 'to the percussion surface, or the working end of 'the percussion element, the hole being provided to allow the lubricant to fiow to the supports.

The rotary eccentric masses according to the invention consist of two metal bodies secured to one another and fixed on the same shaft, a portion of each of these bodies projecting inwardly yand being accommodated in a seat provided in the reciprocating percussion element.

My apparatus is also provided with a device that allows the transmission coupling on the driving shaft to be disengaged, making it possible to bring the apparatus to a standstill, without the necessity to stop the general drive.

One of the many possible embodiments of the invention is illustrated in the accompanying drawings, in which Fig. l is a view, partly in section and partly in elevation, of a percussion apparatus embodying features of my invention;

Fig. 2 is another View with certain parts broken away and other parts shown in longitudinal section, viewed at 90 in respect to the position shown in Fig. 'l.

Figs. 3 and 4 show two cross sections in the planes of, respectively, lines III-411 and IVHIV ofFigl, "Y Y Fig. 5 is a View similar to that of Fig. 1 of a modication;

Fig, 6 is a view similar to that of Fig. 2 of the modied apparatus of Fig. 5; and

Fig. 7 is a cross section in the plane of line VII-VII of Fig. 5.

Referring'now to Figs. 1 to 4 inclusive, the housing A of the apparatus is formed by two sections secured to one another by bolts 2 and The percussion element or hammer B is formed by a mass 6, on which peripheral helical grooves are machined, a central rod 8 and an end piston I0, the latter showing longitudinal inside grooves.

These longitudinal grooves cooperate with oor responding grooves of a cylindric element I2 arranged inside of the piston and secured by means of pins I4 to the cylindric body I6 provided with the end lid of the housing A. Said lid I8 that is provided with the handle 20 is secured to the housing A by means of bolts 4 and is pressed against the peripheral ange of the tubular sheath 22 acting as cylinder for the piston I0.

The grooves of piston IIJ and element I2 have the purpose of preventing any possible rotation of the swinging element B. The helical grooves provided on the striking element 6 and the cylindric body 24 have the purpose to causethrough the unidirectional action of springs of a known tvpe, as shown by Fig. S-the rotation of the drill C, a hexagonal extension of which extends into the threaded sleeve 26. which holds the annular packing 28, the drill C thus being also secured to cylindric body 30 provided with an inside toothing 32. The body 30 fits in a tubular housing member 34 which is secured to the housing A by the bolts 4, whereby the springs 36 absorb the shock caused by thestriking element at both strofe ends. The drill C is held in place by springs 3B secured to the tubular member 34. The eccentric masses consist of two co-axially arranged bodies, each formed by a pivot portion 4i) and a iiyweight portion 42, the latter projecting inwardly and being accommodated in av seat machined in the central rod 8 of the striking element. The rod 8 has flanges 44 which support a bushing 4S to receive the pivot portions 4t of the eccentric masses. The two pivot portions are torsionallv connected to each other by means of front teeth and are at the same time keyed to a centrally threaded pin 43 provided with an eccentric plug 50 which is received in the diametrical'groove 52 machined in the disk 54 that is secured to shaft 56.

The latter is torsionally connected with the element 58, which has front teeth that cooperate with corresponding front teeth of disk 60. This disk is secured to bevel pinion 62 that is in mesh with the bevel pinion 64 which in turn is connected with the motor by means of a flexible shaft or the like. An end lever 68 is provided with a radial pin 10, which engages a helical groove machined in the lid 12, and can be rotated, and thus displaced, so as to exert a pressure through the centre shaft 14 against the element 58, this against the pressure exerted by the 'spring 16, whereby the element 58 is disengaged from pinion 62 and the apparatus can be put out of operation without stopping the motor.

The aforedescribed mechanism unit is supported by roller bearings in a tube 78 that is mounted between the two sections of the housing A and is freely rotatable around the shaft 14 so that for any position of the apparatus in the plane at a right angle to the rotation axes of the eccentric masses the pinion 64, and thus the flexible shaft connected to the pinion, can always maintain the same orientation.

The peculiar vform and arrangement of 'the eccentric masses make it possible to provide an efficient and compact unit,l minimizing the weight of the percussion swinging mass which. results in an increased impactener'gy since the operating speed of the 'mass isv increased. accordingly, V'and the energy increases with the square of the operating speed. The piston il! is designed to form an air cushion vfor shock absorption and energy accumulation purposes, the air being compressed during the return stroke of the piston in the cylindrical chamber BEI and annular chamber 82 so that the useful cross sectional area 'of the piston corrresponds to its outside diameter; A hole 83' machined at' asuitable lieightin the sheath 22 provides a communication between the chambers 86 and 82 andthe outside after the hammer has reached its lowest position. Thus, Vfresh air is admitted and the aircushion and its useful braking action are prevented vfrom becoming ineiective due to leakages between cylinder and piston at each compression stroke.

The lubrication, according Vto my invention, of the movable parts takes place as follows: in the upper section of the housing A is an annular chamber 84 machined which acts as an oil tank. The oil is fed through holes closed with plugs 85 and then ows through radial holes 86 and the corresponding holes 88 in the cylindrical sheath 22 (see Fig. '4) until Vit reaches the sliding surfaces of piston Ill.

Then the oil flows along the piston wall until it reaches the peripheral groove Quinto which radial holes 92 run. By'flovving' through these holes, the oil Vreaches the axial'hole S4 of the reciprocating element` B and then the bushing d6. Below the bushing, the hole S4 is closed by a plug 95 secured to element B by means of the pin 98. The oil flows along the bushing 46 and drops to the bottom of the housing A. From there it flows through holes l and lZ toward the rotating masses, thus lubricating all moving parts of the apparatus. Holes B6 are closed by plugs |04 Vwhich are provided with porous inserts |06 designed to nlter the oil and to allow the oil to now through only in a quantity suljcientV to'wet the piston with lubricant at each operational cycle. Plugs 96 also serve to prevent, by means of their end spigots, any unscrewing of the plugs 104.

The 'embodiment shown in Figs. 5, 6 and 'i shows a percussion apparatus similar to that aforedescribed, except for the fact that it is provided withtwo sets of rotary eccentric masses arranged to oiiset the transverse resultante of the centrifugal force. The parts which are similar to those aforedescribed are marked with the same but primed references. Each pair of rotary masses is provided with a gear |08 and I l0, respectively. Said two gears mesh with each other so that the upper pair of masses, that is directly driven by the driving shaft, causes the lower pair of masses to rotate in the opposite direction. The .resultant of the centrifugal forces which is directed at a right angle in respect to the axis of oscillation, is thus offset on account of the rotation in opposite directions of the 'two pairs of masses. Thus, there is a couple of forces in the plane of the axis due to the distance between the rotation axes of masses, but theset forces are more than enough ofiset by the mass of the whole unit and the action vor the operator. In the position shown in Fig. 5, the iiyweight portions are shown in the lowest position',` whereby the ilywei'ght' portions 42" or the upper pair are on the same level as the pivot portions 4G ofthelowe'r pair of masses. ince both pairs of masses are revolving at the same speed, nointei'ference takes place between same'masses. The arrangement shown allows to minimize the size and bulk` of the unit and the mass of the percussion swinging element B.

The drive disengagement device is similar to that described before; except for 'the fact that the pin 'iii' is rigidly 's'ecuredfto Ythe tube "43', while the helical groove is machined in the lid l2 which rotates together" with vthe end lever et. ACylinder 22' 'isfllubricated in the manner hereinbefore described from 'the oil chamber Sii', while in the hollow insideof element l2 a iurther oil vchamber is provided, into which the oil flows through the upper hole which is closed by theplu'g H2; VThe axial piston H4, which is secured to the bottom of element l2" by means of the nut llt, entersthe axial hole H8 of the element B. The Vsmall or 'inner piston lill has a tubular' extension 12E which is provided with radial holes |22. Oil enters through the holes H22 to get intoan axial opening in the piston mand to new through the noie ne to the bushings 4t of the upper and lower pair of the eccentric masses. The' hammer, while travelling upwards, exerts a given pressure in the hole H3, whereby the air is' Caused to bubble through the lubricant, and the oil chamber is put under pressure. This pressure, while' the hammer is on its return stroke, causes the oil to be forced downwards.

While the invention has been described with some detail, it is to bev understood that the de scription is for the purpose of illustration only and is not to limit my inventive idea. The right is reserved to make such changes in the details of construction and arrangement of parts as will fall within the purview of the attached claims.

I'claim: y

1. Percussion apparatus of the character de scribed, comprising a housing, a reciprocating percussion element including a piston slidably arranged in a cylinder, rotatably mountedec- Vcentric masses, atv least one support for said masses, said supportV being provided on said element, an annular oil chamber provided in the housing, at least one radial hole provided in the cylinder and leading from said chamber to the sliding surfaces of said piston and cylinder, and at least one radial hole and at least one axial hole in said element on the side opposite to the working end of the element, said second named radial hole leading from the sliding surface of 5 the piston to said axial hole, the axial hole being arranged to allow lubricant to new to said support.

2. In the apparatus according to claim i, said piston being provided with a peripheral groove, said groove receiving the lubricant which lubricated the surfaces of the piston and cylinder, said second radial hole allowing the lubricant received in the peripheral groove to now on to said axial hole.

3. Percussion apparatus of the character tescribed, comprising a, housing, a reciprocating percussion element including a piston slidably arranged in a cylinder, rotatably mounted eccentric masses, at least one support for said masses, said support being provided on said element, said piston provided with a peripheral groove, said element being provided With at least one radial hole and at least one axial hole, the peripheral groove receiving lubricant which lubricated the surfaces of the piston and cylinder, said raidal hole allowing the lubricant received in the peripheral groove to iiow on to said axial hole, the axial hole being arranged to allow the lubricant to 'flow to said support.

4. In the apparatus according to claim 1, a cylindrical oil chamber, a piston carrying an extension member protruding into said cylindrical chamber, an axial hole and radial holes in said extension member, and said second named piston being provided with an axial hole, the axial hole of the second named piston communicating with said axial hole in said element.

5. In the apparatus according to claim 1, a diaphragm provided in the hole leading from said chamber to said sliding surfaces to nlter and control the iiow of the lubricant.

6. In the apparatus according to claim l, said eccentric masses being formed by two bodies secured to each other, a portion of each body projecting inwardly and being accommodated in a seat provided in said element.

7. In the apparatus according to claim l, said eccentric masses including at least one pair of lyweights, the iiyweights or each pair being secured to one another by means of front teeth, and being lixed on the same shaft.

8. The apparatus according to claim l, including a driving shaft, a driven shaft for rotatably operating the eccentric masses, and a clutch, said shafts having keyed thereto meshing bevel 6 pinions, the clutch engaging or disengaging the shafts.

9. Percussion apparatus of the character described, comprising a housing, a reciprocating percussion element including a piston slidably arranged in a cylinder, rotatably mounted eccentric masses, at least one support for said masses, said support being provided on said elenient, an annular oil chamber provided in the housing, at least one radial hole leading from said chamber to the sliding surfaces oi said piston and cylinder, and at least one axial hole in said element on the side opposite to the working end of the element, said axial hole receiving lubricant ow along reciprocating surfaces and being arranged to allow the lubricant to flow to said rotating support.

l0. Percussion apparatus of the character described, comprising a housing, a percussion element arranged :for a reciprocating motion Within said housing, eccentric masses rotatably supported by said element to operate saine, at least one support for said masses, a cylindrical lubricant chamber, a cylinder associated with said element and communicating with said lubricant chamber, a piston associated with said housing, said cylinder being movable relative to said piston, the cylinder due to its reciprocating movement forming a chamber of variable volume and intermittently exerting suction upon the lubricant, causing the flow of the lubricant to said rotating support.

GIosUE' PINAZZA.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,177,713 Leonard Apr. 4, 1916 1,620,201 Goldschmidt Mar. 8, 1927 1,629,730 Penberthy May 2li, 1927 1,667,546 Goldschmidt Apr. 24, 1928 1,672,835 Goldschmidt June 12, 1928 1,779,923 Wagner Oct. 28, 1930 1,827,661 Kowarick Oct. 13, 1931 1,855,446 Goldschmidt Apr. 26, 1932 2,350,921 Pinazza June 6, 194,4, 

